Is January 1st a National Holiday?

I always thought that January 1st is a National Holiday, but now i'm not so sure. Some of my friends said that this is a holiday, but no National. I don't know because no one goes to work so I think it is. Everyone knows that on January 1st you cannot buy anything because everything is closed. Do you know if January 1st is a National Holiday?

January 1st is a National Holiday and that's why no one goes to work that day and everything is closed. In the U.S. the Federal law establishes some public holidays for Federal employees and when the National Holiday falls on Saturday or Sunday, it changes to the next monday or to the previous Friday.
January 1st is one of those National days and that's why last year people didn't go to work on January 2nd, because the 1st was on Sunday.

I always thought that January 1st is a National Holiday, but now i'm not so sure. Some of my friends said that this is a holiday, but no National. I don't know because no one goes to work so I think it is. Everyone knows that on January 1st you cannot buy anything because everything is closed. Do you know if January 1st is a National Holiday?